How fast can you stop. Have you tried?

**CB ARGH** · 21st January 2009, 18:42

I gave this a go when I first got the bike. I was very suprised at how quickly it stopped from 60km/h. I have yet to try it at 60km/h in the rain though, now that would be interesting.

**McDuck** · 21st January 2009, 18:50

Originally Posted by skidMark

you lot can say what you want they had cones layed out at wednesday night ride and i did it on morcs rvf400 as well...

Its called skill...

Something no other kb member has.

Are you sure they were not 2-3m apart? I could belive 5-6m fomr a real top rider......

**Jantar** · 21st January 2009, 19:13

Originally Posted by McDuck

Are you sure they were not 2-3m apart? I could belive 5-6m fomr a real top rider......

Not even that. Do the math and at 1 G (the current limit of tyre design) it would take 14.5 m. At a more resonable 0.9 G it works out at 18 m. 2 m is 9 G, so at that he would black out as the human body can only take 5 G of horizontal acceleration.

**Rodney007** · 21st January 2009, 19:19

Originally Posted by skidMark

Yeah i have done a fair bit of practise with this, i could haul the zxr250 to a stop from 60kph in 2 metres.

that was hard hauling em though, and front starts to skitter, but still controllable, beats being a hood ornament.

2 meters?, muhahahahah HAHAHAHAHAHAH

HEEHAHAHAHAHHEHEHE AHAHAHEHEHE (breathe) hehehahahahehehehahaheheah MUAHAHAHEEAEA

**McDuck** · 21st January 2009, 19:21

Originally Posted by Jantar

Not even that. Do the math and at 1 G (the current limit of tyre design) it would take 14.5 m. At a more resonable 0.9 G it works out at 18 m. 2 m is 9 G, so at that he would black out as the human body can only take 5 G of horizontal acceleration.

you would appear to be better at maths than me...

**Rodney007** · 21st January 2009, 19:25

now i understand what you guys mean about mark..

**McJim** · 21st January 2009, 19:36

Originally Posted by Rodney007

now i understand what you guys mean about mark..

Not only that - the poor fella quotes people out of context and makes himself look like a right idiot.

He also crashes barbeques uninvited......

**BMWST?** · 21st January 2009, 19:47

any way get out there and practise...pull on the brakes relatively gently at first increasing pressure as the speed drops.Be ready to release the brake if the wheel locks up(esp the front),but reapply immediately.Be sure its safe,some kind of carpark or something or quiet country road

**racefactory** · 21st January 2009, 20:17

Originally Posted by skidMark

you lot can say what you want they had cones layed out at wednesday night ride and i did it on morcs rvf400 as well...

Its called skill...

Something no other kb member has.

Now i see what the hype about this chap is.

Tell you this, the only thing you're stopping from 60kph that quick around here is a fist through yer fuckin' gob mate. Who are you kidding?

Back to topic: Very good thread! Absolutely, stopping is where a lot of fun is to be had to. On my NC30 i went out practicing and learnt to get it to maximum braking force in the rain by learning at what point the front wheel locks up rather than trying to regulate rear brake to save a 1/100 of braking distance.

After that the dry is not a problem and you can feel the impending lock up qutie easilly.

No need to even touch the rear as all the weight is on the front. I reckon it feels best to concentrate all effort into feeling the impending front wheel lock up.

Though i can't seem to brake as quickly as in my car in the rain before i lock the front. Probably doesnt help with warped discs though.

However I learnt there is still a shitload of braking force in the rain... On my Bt090 tyres, I had the rear wheel lifting off of the ground in the rain before coming to a dead stop- quite a lot of grip. I found as long as you don't slam the brakes on immediately and you make sure to load the front for a split second.

A good practice!!

**98tls** · 21st January 2009, 20:23

Originally Posted by BMWST?

any way get out there and practise...pull on the brakes relatively gently at first increasing pressure as the speed drops.Be ready to release the brake if the wheel locks up(esp the front),but reapply immediately.Be sure its safe,some kind of carpark or something or quiet country road

Good advice,sadly when confronted with an emergency stop many A freeze and do nothing B jump on everything

**gatch** · 21st January 2009, 20:25

whaaaaaaat, you guys cant stop in 2m ?

shitt its a piece of cake, did you see me on mission inmpossible ? did an endo, spun around while pulling my pistol out, shot some mother fuckers, kept spinning whilst holstering my 9, and continued on to the pub for a quadruple absynthe.

get some skills

**Speedracer** · 21st January 2009, 20:34

V=at +Vinitial
d=integral of v.t
d=at^2/2 +Vinitial*t
Vinital = Vkmh /3.6
t = Vinitial / G where G = 9.8m/s/s for '1G'
a = -G

Thus
d=-G(Vinitial/G)^2/2 + Vinitial*Vinitial/G
simplified:
d=-G(V^2/G^2)/2 + V^2/G
d=-V^2/2G + V^2/G
d=V^2/2G

finalise for real numbers
d=(Vkmh/3.6)^2 /(2*9.8G)
d=Vkmh^2/12.96 / (19.6 G)
d=Vkmh^2/254G where G=1 is now 1G

60kmh^2 / (254 *1G) = 14.2m
60kmh@0.9G=14.2 / 0.9G = 15.8m
.....
Assumes no reaction time, no progressive braking blah blah blah which would increase the distance.

**racefactory** · 21st January 2009, 20:41

Originally Posted by Jantar

Not even that. Do the math and at 1 G (the current limit of tyre design) it would take 14.5 m. At a more resonable 0.9 G it works out at 18 m. 2 m is 9 G, so at that he would black out as the human body can only take 5 G of horizontal acceleration.

Hey that's interesting... but are you sure you don't mean that 'friction coefficient' of 1?

Reason I say that is because any light bike with good tyres can pull 1g of force in cornering on the skid pad test. I suspect braking would yield far more force right?

F1 car can pull just over 5g in braking force. From watchin both motogp and f1 i'm guessing a motogp bike can surely pull about 2.5g on the brakes?

interesting.

**Jantar** · 21st January 2009, 20:43

Originally Posted by Speedracer

V=at +Vinitial
d=integral of v.t
d=at^2/2 +Vinitial*t
Vinital = Vkmh /3.6
t = Vinitial / G where G = 9.8m/s/s for '1G'
a = -G

Thus
d=-G(Vinitial/G)^2/2 + Vinitial*Vinitial/G
simplified:
d=-G(V^2/G^2)/2 + V^2/G
d=-V^2/2G + V^2/G
d=V^2/2G

finalise for real numbers
d=(Vkmh/3.6)^2 /(2*9.8G)
d=Vkmh^2/12.96 / (19.6 G)
d=Vkmh^2/254G where G=1 is now 1G

60kmh^2 / (254 *1G) = 14.2m
60kmh@0.9G=14.2 / 0.9G = 15.8m
.....
Assumes no reaction time, no progressive braking blah blah blah which would increase the distance.

Simpler is V^2 = 2*a*d